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US 4,057,320 AGranted
Optical fiber waveguide having minimum modal dispersion
AssigneeBell Telephone Laboratories, Incorporated
InventorEnrique Alfredo Jose Marcatili
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AssigneeBell Telephone Laboratories, Incorporated
InventorEnrique Alfredo Jose Marcatili
Estimating the term…
A graded index optical fiber waveguide for use in an optical communication system is disclosed. The waveguide is a circular symmetric fiber having a cladding with an index of refraction n.sub.2 surrounding a core whose index of refraction is graded from an on axis value of n.sub.1 to a value of n.sub.2 at the core-cladding interface. The index of refraction within the core is defined in terms of a profile function F by the following equation n.sup.2 = n.sub.1.sup.2 (1-F) where F is O on the axis and a function of the radial coordinate r and wavelength .lambda. within the core and satisfies the following equation ##EQU1## where D is a function of .lambda. having a value approximately equal to 2 for minimum modal dispersion and ##EQU2## IS THE GROUP INDEX ON AXIS. The modal dispersion achieved with this design is only a function of n.sub.1 - n.sub.2 and is independent of the profile dispersion ##EQU3##
A circular-symmetric optical fiber waveguide comprising a core surrounded by a layer of cladding material, the refractive index of said layer n.sub.2 being less than n.sub.1, the value of the index of refraction on the axis of the core, and the index of refraction n in said core is graded in accordance with the following equation
A circular symmetric optical fiber waveguide comprising a core having a radius a and an index of refraction n having a value equal to n.sub.1 on the axis of the core, a layer of cladding material surrounding said core the refractive index of said layer being less than n.sub.1, said core having an index grading such that a maximum amount of index-increasing dopant is present on the axis of said core and a maximum amount of index-decreasing dopant is present at the core-cladding interface, characterized in that the profile dispersion of the material in said core is a nonconstant value with respect to radius and is defined by the following relationship ##EQU40## where N.sub.1 is the group index on the axis and F is the profile function defined by the following relationship
Dependencies are inferred from the claim text.